This invention relates to a method of and a catalyst for hydrodesulphurization of gaseous hydrocarbon mixtures.
It is well-known to use a catalyst in the reduction of organic sulphur compounds contained in hydrocarbon feedstocks. A typical catalyst for this purpose is an alumina-supported cobalt-molybdenum oxide catalyst. Typically, the catalyst has been prepared by coprecipitating cobalt, molybdenum and aluminum salts from solution to form a structure where the cobalt and molybdenum oxides are distributed across the surface of the alumina particles. After activation by reduction and sulphidization, the important surface structure is believed to be a mixed cobalt-molybdenum sulphide supported on alumina.
When this structure is prepared by precipitation, it appears that the active form is generated almost haphazardly because of a wide variance in the distribution of molybdenum and cobalt oxides. This means that the active supported Co--Mo--S structure has a relatively low probability of forming.
Another form of alumina supported catalyst is described in Leak, U.S. Pat. No. 3,362,783, in which an adherent film of alumina is formed on a metal substrate and an oxidation catalyst is deposited on the alumina. The catalyst, which may include cobalt and molybdenum, is deposited by impregnation from a solution.
It is the object of this invention to develop a cobalt-molybdenum catalyst of improved efficiency because of improved surface characteristics.